Solar System Walk

A gift to the community from Friends of Galileo Astronomy Club. Dedicated September 22, 2001

For details about the Club, call Becky Kent, 577.4193. For more information about the Solar System Walk or to arrange guided group tours, call Dave Powell, 636.4165.

THE SOLAR SYSTEM WALK AT LAKE SACAJAWEALongview, Washington

This model of our Sun and the nine known planets may help you better grasp the vastness of space.

Polished flush-to the-ground granite markers show the sizes of the planets relative to the Sun and are placed at scaled distances within a 1.64-mile section along the path between Lake Sacajawea and Nichols Blvd., beginning at the 15th Avenue end of the Lake.

Self-guided Tour:

Your journey's starting point: the Sun
The size of our model Sun is about 24 inches. The Sun is made mostly of hydrogen and helium and provides the heat and light that make life possible on Earth. The Sun is also a star. This may surprise you, since the Sun is so much brighter than other stars. By the time you have completed this walk, you will know why the Sun appears to be so much brighter than the other stars. The Sun marker also shows the relative sizes of the nine known planets.

1. Your first stop: Mercury
Tiny Mercury is represented by a yellow disc slightly smaller than 1/10 inch. Mercury moves faster around the Sun than any of the other planets, traveling about thirty mites in one second. The distances in our solar system are so large that in our model Mercury would only move about six feet in one day. Start here

2. Your second stop: Venus
Venus is almost the same size as Earth, but it is a very different planet. The atmosphere of Venus is made mostly of carbon dioxide, which is very good at trapping heat. The surface temperature on Venus is about 9000F, but it is a dry heat, as there is no liquid water.

3. Your third stop: the Earth Moon system
The model shows the Earth and Moon separated by 6 1/4 inches, with the Earth being less than 1/4-inch in size. Consider the size of our model and think back to July 20, 1969, when Neil Armstrong walked on the Moon. The American space program has been able to send men to one other world - the Moon. Imagine how much harder it will be to send men and women to Mars, 115 feet away in our model.

4. Your fourth stop: Mars
Mars is much smaller than the Earth, here represented by a small yellow disc about 1/8 inch in size. Mars has many things in common with the Earth: polar ice caps, four seasons, and a day on Mars lasts just over 24 hours.

5. Your fifth stop: Jupiter
The first four planets are made mostly of rocks. Jupiter is the largest of the planets and is classified as a gas giant. The scaled model of Jupiter is almost 2 1/2 inches. Compare this to the small Earth, at less than 1/4 inch and you can see why Jupiter is called a giant. Jupiter is made of the same elements as the Sun - hydrogen and helium. Jupiter has many moons. The most famous are Io, Europa, Ganymede and Callisto. These four moons are large enough to be seen in the smallest of telescopes and were first observed and studied by Galileo Galilei our club's namesake.

6. Your next stop: Saturn
Saturn is the second largest gas giant and is well known for its beautiful rings. Galileo Galilei was unable to see Saturn's rings in his primitive telescope, but the rings can be seen in small amateur telescopes today.

7. Your next stop: Uranus
Uranus is the first planet discovered using a telescope. Amateur Astronomer William Herschel discovered the planet in 1781. Uranus is also a gas giant and ranks third in size, our model showing the size at slightly more than 1/4 inch. At this time you might be wondering, "just how big is our solar system?" Well, you are now half way between the Sun and Pluto.

8. Your next stop: Neptune
Neptune is slightly smaller than Uranus and is also a gas giant. It was discovered in 1846, after more than 40 years of searching and has a noticeable bluish color. To view Neptune, a larger amateur telescope is needed.

9. Your last stop: Pluto
Pluto is represented by a yellow circle that is less than 1/20 inch in diameter. Pluto is smaller than the Earth's moon. You can see why it took until 1930 to discover the smallest of the nine major planets. Pluto was named following the tradition of naming the planets for mythological Greek and Roman characters. The name Pluto was in part chosen to honor Percival Lowell, an amateur astronomer who led the search for the planet. Percival Lowell did not live to see the planet, but his initials are the first two letters of the planets name.

After Pluto...where?
It you were to continue on your journey to the next nearest star, Alpha Centuri, you would have to travel over 11,000 miles to the southern Indian Ocean to find another 2-foot diameter Sun. The universe is truly a very large place and we hope that you now have a sense of just how big it really is.

About the model
This model of the solar system was inspired by The Thousand-Yard Model or, The Earth as a Peppercorn by Guy Ottewell. In late 1998 the Friends of Galileo discussed creating a permanent solar system model in the local area. After much deliberation and debate, a plan was developed. Lake Sacajawea was considered to be an ideal location.

With the help of the Longview Parks and Recreation Department, the club's plan was adjusted and improved. Enhancements were added to meet requirements of the Parks and Recreation Advisory Board, the City of Longview Historic Preservation Commission and the Longview City Council.

The model was approved by the Longview City Council in Ordinance 2797 on March 8, 2001 and officially presented to the City on September 22, 2001 .

Friends of Galileo is producing a companion study guide for use by schools and youth groups in the community.

Why did Friends of Galileo create the Solar System Walk at Lake Sacajawea?

To bring educational enjoyment to the community for years to come

To appeal to all ages, with special value to youth

To inspire awe and curiosity about the solar system and the universe

To excite present and future generations about the mystery and romance of the scientific enterprise

To convey the preciousness and fragility of our tiny world in the context of the vastness of the cosmos

To help teachers and students team together

To attract visitors to the community

About Friends of Galileo

The club was formed in 1995, dedicated to advancing the understanding and enjoyment of astronomy through educational programs, practical experiences and social interactions. Named to honor early astronomers whose discoveries opened the age of astronomical enlightenment, Friends of Galileo is family oriented and welcomes interested children. The Club holds prescheduled and spontaneous, night sky viewing events at various locations in the local area. Visitors are welcome at monthly club meetings, usually held on the fourth Wednesday at 7 p.m.

For details about the Club, call Becky Kent at 360.577.4193. For more information about the Solar System Walk or to arrange guided group tours, call Dave Powell at 360.636.4165.